Abstract
This paper deals with ship-jacket platform collisions. An examination on NORSOK N-004 rule is carried out. Furthermore, elastic and plastic response of jacket platform is studied. This paper also conducts a sensitivity analysis, focusing on collision points. Simulation models of a ductile and a rigid supply vessel were developed, as well as models of two typical jacket platforms. Data such as collision force, kinetic energy, and deformation energy have been obtained. Several conclusions have been drawn: NORSOK rule underestimates the resistance for certain indention, due to inaccurate description of column deformation mode. Elastic response is extremely important in dynamic analysis of ship-platform impacts, by contributing to reducing impact loads and local energy dissipation. Struck members are therefore subjected to impacts to a low extent, which can be regarded as result of a buffering effect. Before a buffering effect works, a time delay exists. This is caused because the topside has to take up adequate kinetic energy. Striking position has an effect on dynamic behavior of platform. High local strength is in favor of buffering an effect. Elastic response is more significant in a flexible platform than in a sticky one.
Highlights
Offshore jacket platforms are widely used in the oil and gas exploration industry worldwide
The resulting variation of the dimensionless resistance force with dimensionless indentation is shown in Figures 16, 17, and 18, in which w denotes indention, and R, Rc, and D are defined in NORSOK N-004
The resistance-indentation relationship recommended by NORSOK Standard N-004 underestimates the resistance to indentation caused in a shipside collision
Summary
Offshore jacket platforms are widely used in the oil and gas exploration industry worldwide. Located usually many kilometers from land, jacket platforms are subjected to complex environmental loading from wind, wave action, and currents They are vulnerable to collision impact from supply vessels operating around them; this is one of the greatest threats to the platform’s safety. The tube behaves in the manner of a beam and undergoes deflection, which may increase its load-bearing capacity due to the development of membrane tensile forces When this energy is dissipated, the overall response of the platform may be neglected. Axial preload was found to have a substantial effect on the load-bearing capacity, and the capacity for energy dissipation was influenced dramatically They investigated the dynamic behavior of tubes under lateral excitation [3] and found that preloading produced a much more substantial change in dynamic properties in a beam-column cylindrical member, in which global buckling is more important than in a low-aspect-ratio member. The influence of the topside on the structural response of the platform is discussed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
